The results reported in this paper concern two delta Scuties in the Praesepe cluster, namely BN Cnc and BU Cnc, observed during the 1992 STEPHI 4 campaign. Five and six frequency peaks, respectively, were recorded as a result of the campaign. In this work, an attempt is made to identify these frequency peaks as pulsation models, based on stellar structure and oscillation computations. Rotation effects in the frequencies are considered up to second order. Since both stars belong to the same cluster, more severe constraints than for isolated stars can be imposed. Evidence is found to support the presence of mixed modes split by rotation. The frequencies of such modes strongly depend on the input physics to the models and can hence become an important test for the stellar structure theory.